CN1265072A - Hybrid drives for vehicles with auxiliary motors for muscular drive - Google Patents

Abstract

A composite drive device for a wheel-driven vehicle has an electric motor as a first drive source and a pedal drive device as a second drive source, wherein the electric motor has a rotor (9) and a stator (8), has a first rotational speed and a first torque, and the pedal drive device has a second rotational speed and a second torque. The stator (8) of the electric motor is rotatably arranged on an axle or shaft (1) of a transmission system between a pedal crank and a drive wheel, preferably on a wheel axle. The stator can be connected to a second drive source mechanism, and the rotational speed of the electric motor rotor (9) corresponds to the sum of a first rotational speed of the first drive device and a second vehicle speed of the second drive device.

Description

Hybrid drives for vehicles with auxiliary electric motors for muscular propulsion

The invention relates to a compound drive according to the preamble of claim 1 .

Electric auxiliary drives for driver-driven vehicles, such as bicycles, tricycles and wheelchairs, have been known for a long time.

All of these known vehicles are driven by means of an auxiliary electric motor which, in parallel with the muscular power of the driver, drives one or more driven wheels. That is, ultimately two drive sources act in parallel as drive means so that their drive torques are added together.

Thus two drive sources, ie electric motor and muscle force, act on the same drive wheel. The two drive sources are thus coupled according to the rotational speed.

Increasing the rotational speed of one drive source does not necessarily result in a significant increase in travel speed. Conversely, this relieves the other drive source until its power output eventually drops to zero.

This situation can apparently be remedied by utilizing a freewheel mechanism, a disengagement clutch, or the like.

As a result, by using muscle power, it is possible to drive a bicycle with an electric auxiliary drive at speeds above the speed limited by the maximum rotational speed of the electric motor without the electric motor acting as a brake. However, due to the nature of the freewheel mechanism or the disengaged clutch, the electric motor no longer provides any drive power for forward motion at this point.

Therefore, increasing the driver's input does not significantly increase the driving speed, but only reduces the load on the electric motor. For sporty drivers, this often leaves a dissatisfying feeling, so they get used to the increased use of muscle power to increase driving speed even in non-motorized vehicles.

Frequent gear changes are uncomfortable for most cyclists and reduce ride comfort. This situation cannot be satisfactorily resolved by the known shifting methods, be it chain shifters or hub transmissions.

Also in known electric bicycles, the two drive sources, the electric drive and the muscular power, are driven at the same rotational speed. This means, for example, that an increase in the rotational speed of the electric drive (in order to increase the driving speed) must be combined with an increase in the rotational speed of the muscular drive. If the bike has an auxiliary electric drive, this means more pedaling for the driver. However, the average cyclist is only comfortable within a very narrow range of pedaling frequencies. Usually this range is between 50 and 60 rpm. It can of course be brought within a given range by known bicycle gearshifts (chain gear, hub gear). But this means that the cyclist must constantly manipulate the bicycle gearshift.

The object of the present invention is to eliminate the above-mentioned disadvantages as much as possible by designing a sports bicycle with an auxiliary electric motor which converts every additional use of the cyclist's muscular strength into an increased driving speed in every driving situation , resulting in a very sporty riding feel. In addition, manual actuation of the chain shift or hub transmission by the cyclist is minimized. Under the same pedaling frequency, it can travel at any speed.

The two drive sources can be driven completely independently of each other at any rotational speed.

This object is achieved according to the invention by a compound drive having the features of claim 1 . Advantageous among these is the use of electric motors which directly drive the driven wheels/wheels, so-called hub motors.

In the arrangement according to the invention, the two drive sources, the electric motor and the muscle force, can each be driven at completely different arbitrary rotational speeds. The electric motor can, for example, be driven at very high speeds, while the muscle power is driven together at very low speeds (going fast while pedaling lightly), or the complete opposite (going fast and sporty while drawing a small amount of current). The power of both drive sources is always fully converted into forward motion energy and increased travel speed. Since the rotational speeds of the two driving sources are added, or superimposed, each increase in the rotational speed of one of the two driving sources will result in an increase in the driving speed.

So in a bicycle with an auxiliary motor, each increase in power to the rider's pedals increases the speed of travel. That is, a sports-loving cyclist can travel at an arbitrarily fast speed with the bicycle according to the invention. For him there is no constraint range set by the maximum speed of the motor.

Although the pedaling frequency of the cyclist remains unchanged, for the vehicle according to the present invention, the traveling speed can be changed arbitrarily by adjusting the rotation speed of the motor correspondingly according to the pedaling frequency. It can be adjusted by means of corresponding electronics in such a way that the pedaling frequency remains constant over a wide range of different driving situations and actuation of the bicycle transmission is omitted.

The muscle drive mechanism is selectively engageable with the stator or rotor of the electric motor by any kind of coupling means such as dog clutches or ratchets known from hub transmissions. The cyclist thus has two completely different driving modes at his disposal, one for torque-adding parallel drive at slower speeds in mountainous terrain, and the other for fast driving on flatter roads The drive that adds up the speed.

The driving device according to the present invention can be applied in various fields. It is preferably applied in a vehicle similar to a bicycle.

The most commonly used of these are direct drive brushless DC motors. The use of such electric motors is particularly advantageous at the present low rotational speeds. Directly driven motors commutated with brushes are likewise conceivable. In this case, it is advantageous if the adjustment electronics are installed outside the hub, or at least on a fixed component inside the hub. As a result, only two contact rings are required for the transfer of the positive and negative poles.

On multi-wheeled compound vehicles driven by muscular power and electric motors, the drive according to the invention can be installed as an intermediate shaft in the drive train from the pedal crank to the rear wheels. With this arrangement, it is possible to use motors with less torque strength, such as conventional mechanically commutated DC motors, in which the stator - usually constructed as a housing - is driven by muscular force. On the drive unit, the driving speed generated by the muscular and electric drive is reduced and can be transmitted to the driven wheels via a chain or toothed belt transmission.

On bicycles with auxiliary electric drive, the entire drive unit is preferably mounted on the rear wheel. It is advantageous here if the stator of the electric motor and the ring gear driven by muscular force are rotatably mounted on the central shaft. The rotor of the electric motor is configured as a hub shell surrounding the stator, which is connected to the rim by commercially available spokes. The stator is accommodated in the rotor, which is also mounted rotatably on the central shaft, which is designed as a hub shell. It is advantageous - to simplify the installation of the unit - that the hub shell serving as the rotor consists of two parts. To increase driving comfort, the muscular force drive can optionally be positively coupled to the stator or rotor of the electric motor. Various coupling devices can be used for this purpose, such as dog clutches, ratchet couplings known from hub transmissions and others. In the exemplary embodiment shown, a very simple coupling device is used by means of a locking pin.

The rotor configured as a hub can be designed as one-sided mounted, or as a part that completely surrounds the stator and is mounted on each side of the stator with a bearing. In this case, it is expedient if the bearing mounted on the shaft driven by muscular force is configured as a freewheel.

These and other advantageous embodiments emerge from the appended claims.

Two exemplary embodiments of the subject matter of the invention are shown in the drawings and explained with the aid of the ensuing description. in:

Figure 1 is a vertical axial section through a bicycle drive hub;

Figure 2 is an axial vertical section through the wheelchair wheel drive hub.

The embodiment in FIG. 1 shows a possible arrangement of the drive according to the invention on a bicycle, using a brushless DC motor and a one-sided bearing arrangement of the rotor designed as a hub.

In the illustrated exemplary embodiment, the rotor 9 of the electric motor is designed as a wheel hub surrounding the stator, wherein the rotor 9 is driven at a first rotational speed relative to the stator 8 . The stator 8 of the electric motor is rotatably mounted and driven via the ring gear 23 of the pedal drive at any second rotational speed by means of the mechanism described below. The rotational speed generated at the rotor 9 , ie at the hub of the wheel, corresponds to the sum of the first and second rotational speeds.

The bushing 2 is mounted rotatably on the hollow central shaft 1 by means of ball bearings 3 and 4 , which is non-positively coupled to the ring gear 23 of the pedal drive. A flange-shaped part 5 is inserted in one end of the casing 2, and it is connected with the casing 2 through teeth, but can move axially. The flange 7 is rotatably supported on the flange-shaped part 5 via ball bearings and a freewheel 6 . Via a lever 28 with an associated Bowden wire 12 and a return spring not shown in the figure, the flange 7 can be selectively engaged with the stator 8 provided with the bolts 10 or with the rotor 9 provided with the bolts 11 through the holes provided therein. . In this way, the pedal drive can be selectively connected to the stator or to the rotor 9 designed as a non-positive connection as the hub shell. A rotational speed superimposition of the pedal drive and the electric drive or a torque superposition of the pedal drive and the electric drive can thereby be selectively achieved. The force of the muscular force can be selectively transmitted to the stator or rotor of the motor through any coupling device.

The stator 8 is rotatably supported on the central shaft 1 via ball bearings 13 and a freewheel 14 . The freewheel mechanism 14 prevents the stator from reversing when the stator is not being driven together, or when a pedal drive is coupled to the rotor.

Mounted on the stator are stator laminations 15 as well as windings, which are supplied via corresponding devices, in the case shown via slip rings 16 and carbon brushes 17 . Signals for detecting the rotor position are transmitted through slip rings 18 and brushes 20 or the like.

The data about the relative position and relative movement of the stator relative to the rotor detected by the sensor means 19 is supplied to an electronic controller which may be mounted inside or outside the drive mechanism.

In the exemplary embodiment shown, the rotor 9 is designed as a bicycle hub housing surrounding the stator 8 , which is supported on one side by means of ball bearings 21 and 22 on the side opposite the muscular drive. The rotor, designed as a housing, can likewise be constructed as a component that completely surrounds the stator and is supported on both sides of the stator by bearing arrangements in the vicinity of the pedal drive ring gear 23, wherein the bearing arrangements are supported on the bushing 2, while Designed as a freewheel mechanism.

For the driving situation of torque superimposition, namely when pedal drive device is directly coupled with wheel hub (rotor) force, only need to disengage pedal drive device from stator 8 like this. The torque of the pedal driving device can be transmitted to the rotor through the bearing device designed as a freewheel mechanism, and the freewheel mechanism 14 absorbs the reaction moment of the stator to prevent it from reversing.

The drive device according to the invention can also be effectively used as an auxiliary drive device for a wheelchair. What wheelchair mainly uses at present is pure electric driving device, and it is adjusted by manual manipulation. This type of drive is of great help to disabled persons who can no longer drive the wheelchair by their own power. But by doing so they lose out on all the daily physical activity, which is very health-promoting.

A fully muscular powered wheelchair with tire-shaped powered armrests is a very suitable and simple solution, but places an undue physical burden on the disabled.

Based on the experience that physical exercise is particularly important for people with disabilities, the wheelchair has been developed to detect the force exerted by the driver through sensors in the armrests, which will be amplified by electric motors mounted in the hubs. Its effect on driving a wheelchair is similar to that of power steering.

However, there remains an unresolved problem in that it is difficult to travel faster than walking speed by driving the handrail.

This problem can be solved in a completely new way by the drive device according to the invention. Preferably, direct-drive electric motors are installed in the hubs of both wheels, the rotatably mounted stators of which can be driven by muscular forces acting on the tire-shaped armrests. In this way, the first rotational speed generated by the electric motor and the second rotational speed transmitted to the stator by the rider through the handrail will be superimposed. The rotor is connected to the rim via the spokes or directly, on which a third rotational speed occurs corresponding to the sum of the first and second rotational speeds. While on the armrests the drive is only at a speed close to walking speed, on the rim a high drive speed can be achieved without much effort. A larger moment is required on the wheel when going uphill, for which purpose a second tire-shaped handrail is operatively connected to the rotor, ie the wheel rim. If a drive is made on this armrest, no rotational speed superimposition occurs; instead, the torques of the armrest drive and the electric drive are superimposed.

In this way, the wheelchair can be equipped with a drive that alternately amplifies the force acting on the armrest according to the needs or desires of the rider - for use when going uphill or when winding around - or doubles the rotational speed acting on the armrest . To switch from one driving mode to another, it is only necessary to drive on one or the other armrest. It is expedient for this to use two armrests adjacent to each other or two armrests of different diameters per wheel. It is also conceivable to use one armrest per wheel, which is operatively connected to the stator or rotor of the electric motor by suitable coupling means.

A preferred embodiment of a drive is obtained in that the rotor and the stator of the electric motor are supported on a central shaft. It is advantageous if the rotor and the stator are each configured as a disk-shaped part, the rotor surrounding the stator and configured as the hub of the wheel. Depending on the diameter of the wheel and the rotor, the hub-shaped rotor can be connected to the rim via spokes or transition to the rim, respectively. The embodiment with two armrests per wheel has proven to be a technically very simple and very easy-to-handle solution when switching between the two modes of drive. When driving on the outer armrest directly connected to the rim (rotor), in order to receive the reaction torque on the stator, a freewheel mechanism that locks in the reverse direction is provided. Mounting the adjustment electronics on the stator allows power to be transmitted via only one slip ring for the positive pole, while the negative pole is transmitted via the frame. For detecting the power applied to the armrest connected to the stator, a sensor for detecting the relative rotational speed between the stator and the fixed shaft is sufficient.

The embodiment in FIG. 2 shows a possible arrangement of the drive device in the wheel hub of the wheelchair. In the illustrated embodiment, two armrests 40 and 50 are used, one armrest 40 being force-coupled to the stator 20 and the other armrest 50 being force-coupled to the rim of the wheelchair (rotor of the electric motor).

Both the stator 20 and the rotor 30 are rotatably supported on a center shaft 101 through ball bearings 70 and 80 or 90 and 100 . One bearing for the stator preferably uses a freewheel mechanism 80 which prevents reversal of the stator when driven on the outer armrest 50 only.

In the exemplary embodiment shown, the rotor 30 designed as a housing is connected to the rim 60 via spokes 170 . A magnet 180 is arranged inside it. The magnet together with the stator piece 190 and the stator winding 200 mounted on the stator 30 constitutes a motor generating the first rotational speed.

On the inner second handrail 40 connected to the motor stator 20, it is driven by hand at the second rotational speed. This rotational speed is detected by the sensor 140 and the first rotational speed of the matching electric motor is added to it by the control electronics. The third rotational speed generated at the rotor 30 of the electric motor, ie at the rim of the wheel, corresponds to the sum of the first and second rotational speeds.

On the outer armrest 50 connected to the wheel rim, it is driven at a first rotational speed corresponding to the rotational speed of the electric motor. In this driving state, the torque applied to the armrest 50 is amplified by the motor. In order to absorb the reaction torque now occurring on the stator—the stator is at rest in this drive state—a reverse locking freewheel mechanism 80 is provided. To detect the power applied to the outer handrail, a sensor 250 is provided.

In the illustrated embodiment, the adjustment electronics 110 are mounted on the stator. It is powered via carbon brushes 120 and slip rings 130 . The negative pole is conducted through the frame.

Flange-shaped parts 210 and 220 are respectively provided for receiving carbon brushes 120 or slip rings 130 and sensor 140 .

In order to detect the power applied on the armrest 40, it is only necessary to detect the rotational speed of the stator relative to the central axis through the sensor 140. The relative rotational speed of the rotor relative to the stator and the respective rotor position are detected by the sensor 150 .

For very practical wheelchairs, it is sufficient to adjust the wheelchair only by the rotational speed of the rotor detected by the sensor.

When driving on the outer armrest 50, the driving torque can be amplified by the electric motor. For this purpose, a further sensor 250 is provided on the outer handrail, which detects the power exerted by the cyclist on the outer handrail. Especially when going uphill, the torque applied to the outer armrest can thus be amplified by the electric motor. However, it is also necessary for this to transmit the signal of the sensor 250 to the electronic control unit which rotates with the stator. In the illustrated embodiment, this is accomplished by brushes 230 and slip rings 240 .

Claims (12)

1. A compound drive device for a wheel drive vehicle with an electric motor as a first drive source having a first rotation speed and a first torque and a second drive source having a second rotation speed and a second torque, wherein the Said electric motor has a rotor and a stator, characterized in that the stator of the electric motor is rotatably supported on the axle or shaft of the drive train between the pedal crank and the drive wheel, preferably arranged on the axle and mechanically connected to the second drive source. The coupling enables the stator to be driven by the second drive source, and the rotational speed of the rotor of the electric motor corresponds to the sum of the first rotational speed of the first drive means and the sum of the second rotational speed and the second rotational speed of the first drive means. 2. The compound drive as claimed in claim 1, characterized in that the second drive source is alternately coupled either to the stator or to the rotor such that the torques or rotational speeds of the two drives are added. 3. The compound drive device of claim 1, wherein the second drive source is a muscular force drive device. 4. The compound drive of claim 1, wherein the electric motor is an outer rotor motor. 5. A compound drive as claimed in claim 4, wherein the stator is rotatably arranged on the axle of the driven wheel and the rotor is part of the hub. 6. The compound drive of claim 1, wherein the motor is an electrically commutated motor. 7. The compound drive device according to one of claims 1 to 6, characterized in that a freewheel mechanism is introduced between the stator of the first drive source and the second drive source. 8. Compound drive according to one or more of claims 1 to 7, characterized in that a freewheel mechanism is introduced between the shaft driven by muscular force and the rotor of the electric motor driven at the first rotational speed. 9. Compound drive according to one or several of claims 1 to 8, characterized in that the vehicle is a bicycle. 10. Compound drive according to one or several of claims 1 to 8, characterized in that the vehicle is a wheelchair and that a compound drive is mounted in each of the two driven wheels. 11. The compound drive according to claim 2, characterized in that a bushing (2) is mounted on the axle, on which the ring gear of the muscle-driven drive is arranged, wherein the bushing can be mounted on The axially movable first flange (5) on the casing is fixed in shape, and the movable 0 The second flange (7) can be moved on the first flange (5) via the freewheel mechanism (6) by means of an intermediate bearing arrangement in such a way that the second flange can be alternated via form-locking means (10, 11) The ground is engaged with the stator or rotor of the electric motor. 12. The compound drive device according to claim 1, characterized in that sensors are arranged on the stator and the rotor, the sensors detect the relative movement of the two motor parts, the signals thus detected are transmitted to the adjustment device, through which The adjusting device can adjust the electric motor.

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